* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }

  li {
    list-style: none;
  }

  .main {
    width: 700px;
    margin: auto;
    background: #000;
  }

  .slides {
    height: 320px;
    position: relative;
  }

  .slides ul li {
    /* display: none; */
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    /* 这里实现淡入淡出的关键 */
    transition: all .3s;
  }


  .slides li.active {
    /* display: block; */
    opacity: 1;
  }

  .slides .extra {
    width: 700px;
    height: 53px;
    line-height: 53px;
    position: absolute;
    bottom: 0px;
    background-color: rgba(0, 0, 0, 0.8);
    z-index: 10;
  }

  .slides .extra h3 {
    width: 82%;
    margin: 0;
    margin-right: 20px;
    padding-left: 20px;
    color: #98E404;
    font-size: 28px;
    float: left;
    font-weight: 500;
    font-family: "Microsoft Yahei", Tahoma, Geneva;
  }

  .slides .extra a {
    width: 30px;
    height: 29px;
    display: block;
    float: left;
    margin-top: 12px;
    margin-right: 3px;
    background-image: url(./assets/icon_focus_switch.png);
  }

  .slides .extra .prev {
    background-position: 0 0;
  }

  .slides .extra .prev:hover {
    background-position: -30px 0;
  }

  .slides .extra .next {
    background-position: -60px 0;
  }

  .slides .extra .next:hover {
    background-position: -90px 0;
  }

  .indicator {
    padding: 10px 0;
  }

  .indicator ul {
    list-style-type: none;
    margin: 0 0 0 4px;
    padding: 0;
    overflow: hidden;
  }

  .indicator ul li {
    position: relative;
    float: left;
    width: 60px;
    margin: 0 4px 0 5px;
    text-align: center;

    cursor: pointer;
  }

  .indicator li img {
    display: block;
    border: 0;
    text-align: center;
    width: 60px;
  }

  .indicator li .mask {
    width: 60px;
    height: 60px;
    position: absolute;
    top: 0;
    left: 0;
    background-color: rgba(0, 0, 0, 0.4);
  }

  .indicator li .border {
    display: none;
    width: 54px;
    position: absolute;
    bottom: 0;
    left: 0;
    z-index: 20;
    border: 3px solid #98E404;
  }

  /* li里面的mask 和 border 刚开始都是显示的 */
  /* 我们写一个样式css */
  .indicator .active .mask {
    display: none;
  }

  .indicator .active .border {
    display: block;
  }